Valve-receiver for wireless signals.



G; M.-WRIGHT.

VALVE RECEIVER FOR WIRELESS SIGNALS. APPLICATION FILED MAR. 13. 19111,243,789. Patented Oct. 23, 1917.

' I UNITED. STATES PATENT v onnron.

' ononon MAURICE wnronr, 0? LONDON, Enchant, nssronon 'ro mncom wmnnnssTELEGRAPH COMPANY OF AMERICA, .N'EIKT YORK, N. Y., A CORPORATION OF NEWJERSEY.

vnLvn-nncmvnn non WIRELESS srcnans.

Patented Oct. 23, 1917.

Application filed Eareh 18, 1917. Serial 1V0. 154,580.

To all whom it may concern: -Be it known that I, Gnonon MAURICE WRIGHT,a subject of the King of Great Britain, and resident of Marconi House,Strand, London, England, have invented a new and useful Improvement inValve- R-eceivers for Wirele$ Signals, of which the following is aspecification. This invention relates to receivers ofwireless signalswhich comprise a vacuous vessel containing a heated filament, a grid andan anode. I

'According to this invention I connect the oscillatory circuitcarrying'the oscillations to be detected'to the grid and anode, and Iprovide means for applying a steady potential to the gridwith respect tothe filament, and I am thus enabled to limit the current which can flowin the anode circuit. One important result of this will be that a thesounds caused by atmospherics in a telephone will be reduced and willthus be prevented from overpowering the sounds caused by the signalswhich it is desired to detect.

With this arrangement the space between the grid and anode constitutes adetector or conductive coupling of extreme sensitiveness for very smallvalues of limiting current, the limiting current being decided by thebrilliancy of the filament and the potential at which the grid ismaintained with respect to the filament.

I-prefer a'brightly glowing filament and: -a potential adjusted to givea, very small limiting value to a dull filament and a potential of ahigher value.

A very small potential difierence between the anode and grid isnecessary for adjustment, at the most a small part of a volt asdistinguishedv from tubes employed for magnifying. I find that the tubeswork best at the highest possible vacua and I prefer grids of a finemesh.

My invention is illustrated by the accompanying drawings, Figure 1 ofwhich is a diagram showing my invention adapted for .use as adetectoriand Fig. 2 is a modification -'in which two tuned oscillatoryclrcults are employed connected to each other by a con ductive coupling.Fig. 3 shows a curve of current for difierent potentials on the anode,the abscissze A representlng potentials and the ordinates 0 current.Fig. 4 shows a modified form of valve in which the grid and anode are soformed that they completely surround the filament. I

In Fig. 1, a isa vacuous tube containing a grid (1, anode e and filamentb heated by battery 0 in series with a resistance 8 for adjusting the,brilliancy ot the filament. Though the grid and anode are shown in theconventional manner, I prefer to so form the grid that it completelysurrounds the filament, and the anode that it surrounds the grid. Thisconstruction is shown in vertical section in Fig. 4. An inductance f,coupled to an aerial i'and shunted bya condenser g, is connected totheanode e and through a potentiometer p to the grid d, and is coupledto a telephone receiver m by coupling The grid 0? is also connected by avariable contact to a resistance t across thebattery c. For a givenposition of this variable contact on the resistance t, a certainlimiting current can flow across the space between d and c with a givenbrilliancy of the filament; This maximum current I call the saturationlimit or saturation current. The circuits are so arranged that thebrilliancy of the filament can be adjusted by s, the potential of thegrid can be adjusted by t, and the most sensitlve point on therectifying curve can be utilized by p, so that signals can be heard inthe telephone, the maximum strength of these signals being limited bythe adjustment of t. That is to say, by varying the potential applied tothe grid with respect to the filament, the operator can make only asmall portion ofthe filament In Fig. 2, signals in the aerial aretransferred inductively to the circuit f g, and the space between thegrid 03 and the anode e acts as a conductive coupling between the twocircuits f g and 7c Zby completing a circuit through k, g, potentiometerp, 0, and f the circuit is, Z being coupled to the detector circuit a.The limiting value of the current is controlled, as before, by t and thesensitive pointisfound by the potentiometer p. g is a choke coil and r acondenser shunting it, and o is a reaction-coil for balancingacofmorethana' certain strength. Moreover,

sounds caused by static disturbances might otherwise-be louder than thesignals and overpower the latter. This limitation of the signals andother responsive sounds in the receiving circuit is obtained by varyingthe current in the filament Z) so as to control the brilliancy thereof,and consequently the quantity of electrons which may be given off by thefilament, as well as by varying the position of the contact at If tocontrol the potential between filament b and grid g. The latteradjustment is the preferred one and is used as far as possible, beingmore efficient, since the distinctness of the received signals ismaintained practically unimpaired, although their maximum loudness islimited. This result is due to the quick rise of the current to itsmaximum, the rate of increase of the current increasing. with thebrilliancy of the filament and the maximum current for a ing determinedby the position of the contact at t. The method of limiting'the received signals by reducing the brilliancy of the filament is disclosedin British patent claim is:

1. In three-element vacuous detector, comprising anode, grid, filamentand heat: ing battery, a resistance connected across the battery, and aconductor connected at one end directly to the grid and at the other endby an adjustable contact to the resistance, said filament and heatingbattery being otherwise disconnected from said anode and grid.

2. The combination of a .vacuous vessel containing a grid, an anode, anda filament, a battery connected to the terminals of said filament, aresistance-connected across said battery, to said grid and at the otherend to an adjustable contact on said resistance, in comgiven brilliancybe- 1 a conductor connected at one end neespse bination with means forimpressing the oscillations to be detected on the grid and anode only,all for the purpose described.

3. The combination of a vacuous vessel, containing a filament, a grid,and an anode, means for heating the filament to varying degrees ofbrilliancy, tential applied to the grid and having a value of the sameorder as the potential drop across the filament, means for adjustingthis potential to obtain any required saturationlimit, and anoscillatory circuit connected to the anode and to the grid, saidadjusting means being connected to said oscillatory circuit only at saidgrid. 7

a. The combination of a vacuous vessel containing a grid, an anode, anda filament, a heating battery connected to the terminals of saidfilament, a resistance connected across said battery, a conductorconnected at one and directly to said grid and at the other end to anadjustable contact on said resistance, and an oscillating system forreceiving signals connected to said grid and anode, said systemincluding means for applying an adjustable potential across said gridand anode, said filament and heating battery being entirely disconnectedfrom said system except for the connection of said conductor directly tosaid grid.

5. The method of operating a vacuous com.

tamer having a filament and anode therein, With a grid intermediate saidanode and filament which consists in impressing a con-.

tinuous M. F. on saidfilament, 1mpressing a portion only of said E. M.F. between the grid and filament, and impressing intermittent potentialimpulses across the grid and anode, .but none between the filament andgrid.

6. The combination of a vacuous vessel containing a grid, an anode, anda filament, means for impressing a desired continuous potential acrosssaid filament, means for impressing between said filament and grid aportion only of said continuous potential, and means for impressingoscillations to be received between said grid and anode only, theconnections being such that no intermittent potential impulses areimpressed on said filaments.

a n rmally fixed po-,

' In testimony that l claim the foregoing as my invention, T have signedmy name this 16th day of February, 1917.

